The process of shingling one’s roof can be relatively simple, given a few factors for initial consideration.
If a roof is very steep or located high above ground level; it can become a safety issue for someone not properly trained to work at heights, or who may not have the appropriate equipment to complete the job safely and effectively.
It is also important to consider that shingle roof installation, and associated tear-off of the existing roof shingles (if replacing an existing shingle roof); can be very heavy work. Therefore; it is important to consider well and honestly, one’s ability to lift, bend, stretch, and climb. The roof is certainly no place for someone who has a fear of heights or stepping on or off ladders at any heights above the ground.
Further to consider is the time involved to install a shingle roof. Particularly when removing shingles; the installer, amateur or otherwise; must always be conscious of, and prepared to close in the open roof sections under threat of inclement weather or flash storms.
For many homeowners and cottagers, doing a simple “A frame” roof, or shed project could be well within their capability. However; details such as dormers, valleys, flat roof tie-in junctions, snow basins, etc., may require a level of expertise to make such areas watertight; beyond which most people have experience or training.
Also for consideration is the liability. Gathering a few friends or neighbours for help, may seem to be a great way to save money, but in the event, someone falls or gets injured accidentally; the consequences can be costly, or traumatic if someone ends up seriously hurt.
So whether one chooses to do their own roof, or enlist the services of a professional roofing contractor; having a good understanding of the process, and the important details required for a successful shingle roofing project, will help insure a highly satisfactory result.
If you have ever watched a professional roofing contractor complete a shingle roof installation, they can make the job look easy. There is a lot to know, however, and a lot of science in the methodology involved.
The following steps should be considered to result in a superior shingle roof installation.
1) Do it right or don’t do it at all.
Shortcuts, poor quality materials, or poor quality labour will result in a bad job, or a job that does not last. Consider the following:
- Poor materials & good installers can equal a bad job.
- Good materials & poor installers can equal a bad job.
- Poor materials & poor installers always equal a bad job.
- Good materials & good installers equal a great job.
For most people, this should make sense. However, among the highest categories of complaints received by the Better Business Bureau, roofing contractor complaints are near the top of the list.
2) Select the right roof shingles and related materials for the job.
In many instances, roofing materials comprise about one-third of the total job cost. This can fluctuate based on the grade and style of shingles to be selected.
When selecting roofing shingles, it is important to do one’s homework. For example, at one time period or another, many shingle manufacturers have had quality control or product failure issues. This could be said of many mass-produced products in the market today. What is important; is how the shingle manufacturers have handled such issues with consumers. Do research with professional roofing contractors, and through on-line searches for shingle manufacturer warranty claims.
It is also very important to read the fine print associated with shingle product warranties. Although manufacturers typically promote specific warranty periods for particular shingle products that are similar; such as 30 years, or limited lifetime, etc., there can be vast differences between what the purchaser may actually receive when having to claim on a shingle warranty.
The market over the past decade has shifted to fibreglass laminate type shingles. Previously; three tab “organic” asphalt shingles had been the go-to product for decades, particularly in the eastern U.S. and Canadian markets.
Today’s fibreglass shingles offer advantages in their construction. They are less prone to curl or claw after many years. They have no slots or cut-outs between the tabs; therefore helping to guard against water backup due to ice dams, etc. Such roof shingles have a woven fibreglass matt serving as the core of the product. Asphalt saturates the matt and provides waterproofing characteristics. Ceramic granules are embedded in the top surface asphalt pour of the shingles. Their appearance mimics the look of cedar shingles or slate tiles.
So once you have selected the style and grade of shingles for your roof replacement; the next step is to select underlayment materials, and metal flashing details, necessary to complete the job. Such materials and their application, are described in further detail below in this article.
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3) Evaluate and prepare the site.
This can involve the rental of a disposal bin or dump trailer to haul away the old roof shingles and related debris. It is important to lawfully recycle or dispose of the old roofing materials. Heavy fines can be levied against property owners if it is discovered that such materials have been dumped illegally. If hiring a contractor for the job, ask the contractor to provide proof of lawful disposal by means of disposal receipts. Few people know that if caught, the source from which the illegally dumped materials came from, can be fined. In other words the homeowner.
Place plywood around the home to protect windows, doors, shrubbery, etc. which may become damaged as a result of debris being dropped from the roof. It is a good idea to have a ground person whom can signal workers on the rooftop, whom may be dropping the debris, and to protect passers-by, or people existing the home unknowingly. Further protection measures can involve hanging tarpaulins from guttering to protect neighbouring siding, etc.Make a plan where the roof shingles can be dropped safely and conveniently. The person appointed on the ground for safety can also load the debris into the waste receptacle using wheelbarrows, trash cans, etc. This progresses the cleanup as the roofing work proceeds.
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4) Working safely is working smart.
Professional roofing contractors are mandated by law to use fall arrest equipment when engaging in work on the roof. They are further required to comply with various laws involving health and safety.
If undertaking such work as the homeowner, the same common sense procedures should be applied. Approved roof harnesses, lanyards, and ropes secured by brackets into the roof are required for workers to protect against falls. Before using such equipment; persons need to be trained in the proper use and type of fall arrest equipment, before attempting to enter the roof.
Tying a rope around the chimney does not cut it. In fact, it is extremely dangerous. So if you hire a professional roofing contractor for such work; be sure to obtain copies of their fall arrest certification, and their company’s health and safety policy. Professional roofing contractors will be pleased to demonstrate such credentials. You always, need to verify proof of proper liability insurance, and workers compensation clearance certifications. In Canada, homeowners who do not exercise this due diligence can become liable in the event a worker is injured on their property; even if the worker does not work directly for them. A home owner’s insurance will not cover such perils.
5) Tools required for completing a shingle roof installation.
On the checklist, items should include a roofer’s hammer, and or a compressor with sufficient lengths of hose to reach the field areas of the roof. If using a compressor; an automatic roofing nail gun, and a sufficient amount of coil roofing nails will be necessary. 1-1/4” galvanized roofing nails are typically used for application of new roof shingles overboard or plywood decking.
Also required will be a utility knife with refills of hook blades for cutting the shingles. A tape measure, chalk line, powdered chalk, wonder (pry) bar, tin shears, and a caulking gun, represent the key hand tools necessary to complete a shingle installation. It is also a good idea to have a chord-less circular saw and reciprocating saw for cutting and replacing damaged roof decking and for cutting vent holes.
Tools used in the removal and cleanup of roof shingles include roofer’s spades which have serrated teeth at the base of the shovel (useful for prying nails from the roof deck), and or pitch forks for tearing up the shingles. Large mouth, coal shovels are best for ground cleanup duties, along with a sturdy wheel barrow(s).
Purchase large tarpaulins in the event that one must cover open roof sections in a hurry, and or to protect unfinished roof areas if the project will take more than a day.
Obtain a quality ladder(s) designed for the weight of the person using the ladder. Inspect the ladder to insure that there are no bent rungs or feet, or bends in the frame of the ladder. If it is suspect, simply don’t use it. Never forget to tie the ladder off at the top of the gutter.
Always extend the ladder above the roof line. The ladder should be erected at a rate of one foot out for every four feet up. It is a good idea to secure the base of the ladder and to insure that the ladder is placed on even, solid ground.
In many instances; the use of scaffolding is a preferred choice for dealing with areas which will require extreme ground protection, or where the roof is very high, and or very steep. Scaffolding should have protective guard rails, and be erected by a qualified scaffolding supplier. Some municipalities will require permits for erecting scaffolding, particularly where pedestrians may be vulnerable.
To stand safely on the roof; purchase metal roof jacks which can be nailed into the roof at rafter locations. A 2”x10” plank or planks can be placed onto the roof jacks to provide a stable footing, place materials, and act as a working platform. Always wear fall arrest equipment in the event a jack ever let’s go.
Check in the attic if possible, to determine what the roof decking is comprised of. If it is dimensional lumber or plywood; having a supply on hand, to replace any rotted or damaged roof decking will be necessary to be prepared.
If the roof is plywood, and there is a wavy appearance across the surface of the roof, or if it sounds “crunchy” or feels soft under foot; it is a sign that the entire roof surface decking should be replaced. This can be caused by dry rot, water damage, or undulation which has resulted from the plywood becoming wet in the winter and drying out in warmer weather. This often signals that there can be a ventilation issue with the roof. The result over time is that the plywood will delaminate, and or become wavy. (Much like a piece of paper that gets wet, and is then allowed to dry).
Also when checking the attic look for evidence of mould on the underside of the decking. Often evidence will appear around nail protrusions, signalling frost occurring under the decking during colder months.
While observing in the attic; look for daylight around the perimeter roof edges. If it is not present; you may have to increase, or add intake ventilation at the soffit areas of the roof. It is important to note that shingle manufacturers will require proper ventilation for their shingle product warranties to be valid. A properly vented roof will function more toward the lifespan for which the shingle was designed.
The next consideration prior to beginning the shingle roofing job, is how you will get the shingles up to the roof. If the roof pitch is not very inclined; some suppliers will conveyer the shingles from their trucks onto the rooftop. Another option is to consider the rental of a ladder hoist, which operates off a gas or electric motor. Carrying up shingles to the roof is not considered a best practice, particularly by amateurs. Ladders are not designed to be a working platform. Safety requirements are such that one must maintain at least three point contact with the ladder at all times.
6) Let’s get started on the roof.
Begin by removing the cap shingles at the top of the roof. Using your ripping spade, begin to remove the roof shingles starting at the peak of the roof, and working downward to the eaves area. Remove only an area that you can comfortably close in during the same day. It is a best practice to start at the exterior edge (rake edge) on a gable or shed style roof. Carefully drop the old roof shingles to the ground.
The exposed roof deck will require that any protruding roof nails will have to remove or hammered in. Check that the roof boards or plywood are secured properly at rafter locations. As necessary, add galvanized spiral nails to re-secure the decking. Note that with some higher end shingles, the manufacturer may require a layer of plywood to be nailed over old plank decks. Sometimes manufacturers will suggest making lateral cuts in old plank decks to prevent cupping of the planks. This prevents telegraphing into the appearance of the shingles. Old lumber can warp or cup, so this procedure needs to be used in such conditions are observed.
Whether the deck is plywood or board construction; any decking that exhibits rot, or cracks or holes, must obviously be removed and replaced. Boards can be cut between rafter centres and spot replaced as required. Plywood sheets can be individually removed and replaced with similar dimensional sheeting. If all of the deckings is substandard; it is better to use a minimum of ½” plywood. Once the decking has been replaced or repaired, roofing can begin.
At the bottom roof eaves areas; begin by installing a good quality ice and water membrane. Such membranes are a peel and stick type of operation. Carefully remove the backing, and adhere the product to the roof surface. The ice & water membrane should extend a minimum of 24” past the heated interior wall the house. So depending on the width of the roof’s overhang, and the pitch of the roof, this will determine how many courses of the membrane will have to be installed up from the bottom of the roof. The balance of the exposed roof deck can then be covered with a synthetic underlayment, or fibreglass felt paper. Exercise best efforts to minimize any horizontal cuts or seams you will have in the underlayment. Stagger laps at least three feet between courses, when laying such underlayment. The underlayment can be secured with roofing nails or cap nails if the membrane will be acting as a temporary water barrier.
Underlayment which intersects valley areas (assuming the use of open valleys); should extend 6” over the valley metal. (Valleys refer to opposing roof slopes which form a channel where they intersect). Whether installing open metal valleys, or closed type shingle valleys; it is recommended to install one course of ice & water membrane beneath the valley material. Such material should be laid in equal proportion from the centre of the valley area. This serves to provide protection from wind-driven rain and ice back up in the valley areas.
It is a recommended practice to install drip edge metal flashing at the bottom roof eaves areas. Such metal detail can be installed beneath the first course of ice and water membrane. It can also be installed over the course of ice and water membrane. In doing so, an added strip of the membrane material should be applied over top of the exposed metal drip surface, which is laid on the roof deck portion. This is referred to as “enveloping” the drip edge flashing. Drip edge materials should be pre-painted, galvanized steel or heavy gauge aluminum. It is further suggested that such metal should be fabricated with a hemmed exterior edge, to prevent the risk of cuts when cleaning out the gutter.
Drip edge metal applied at roof eaves areas serves to better direct water into the gutter, and to prevent water dripping off the roof shingles, from curling back underneath the fascia board, roof board/decking junction. It also can serve as a barrier against water backing up from the gutter and may help resist animal intrusion at this vulnerable area.
Also suggested is the installation of metal flashing along the rake edges of the roof, which can help secure underlayment, and increase wind resistance at the edge of the roof. Such metal should be nailed over the underlayment material at the roof’s edge (rake).
It is considered a best practice to apply starter type shingles (specifically designed by the shingle manufacturer) along the exterior rake edges of the roof, in addition to the requirement of applying a starter course of shingles at the roof eaves areas. If installing open type metal valleys; starter shingles should be applied along both opposing sides of the valley metal, where chalk lines have been struck, to create the valley channel. Starter shingles refer to a specific type of shingle manufactured for the purpose of sealing the roof shingles at the bottom roof eaves areas, rakes and to act as valley liners. This particular shingle has a ribbon of adhesive which helps seal the exposed “field” shingle to be applied.
While certain roofers may have competing viewpoints, it is generally accepted that open metal valleys are a preferred method of installation, particularly in regions which experience snow conditions. The evidence shows that under such conditions; closed shingle valleys tend to wear out more quickly, as a result of constant water shedding in the valley areas, and that metal is preferred because it provides less friction where snow and ice may “stick” in the granule surface of the shingles more easily.
Metal valleys should be a minimum of 24” wide. The preferred gauge is 26, but 28 gauge is acceptable in most areas. Pre-painted galvanized steel is recommended. Valley metal is laid over the ice and water membrane liner in the roof valley area. On long valley applications, each sheet of metal should be applied at least 12” over the preceding sheet, in such a manner as to promote the shedding of water. It is suggested to apply a healthy bead of sealant underneath each adjoining valley sheet, or to apply mastic compound under such overlapping metal.
Where metal valleys meet the roof eaves areas; the metal should be trimmed to correspond with the interior 45-degree angle of the roof. Leaving the metal too long will result in the water shooting past the gutter. Leaving the valley metal short at the eaves, with exposed shingle courses, will result in premature and unnecessary wear of the shingles in the area.
When joining metal valleys at the peak of two opposing sides of a slope, or dormer; the metal valleys should be cut to overlap one another along the ridge of the slopes and against the field surface of the roof. Application of sealant in these vulnerable areas should be completed. A skilled roofer can lock seam such metal together at such junctions of a valley, but this method is typically not within the skill set of a do it yourself.
Once the valley metal is installed; snap two chalk lines on each side of the valley. Measure 2-3” from the centre of the valley, at the top of the valley, and on each side of the valley. At the base of the valley, repeat the exercise but allow 1/8” extra width for every three feet of the length of the valley. The result should be two chalk lines reflecting a tapered profile from top to bottom. Starter shingles can be applied along the exterior edges of the chalk lines. Nails should be placed so that they are at least six inches away from the edges of the chalk line. A ribbon of caulk should be applied beneath the starter shingles in a zig-zag pattern, but not so the caulking will squeeze out past the clean edges of the starter shingles.
When applying field shingles which reach the valley areas, keep nailing back at least 3 “ from the exposed valley edges, and trim small triangular pieces off the tops of the shingles where they meet the valley edge. This will help shed water away, and direct water toward the valley area. Some shingle manufacturers suggest applying sealant between courses of shingles that meet valley edges.
7) Starting the application of roof shingles.
With the base starter shingles applied at roof eaves and rakes, and valleys; now the “field” shingles can be applied. Read and follow the instructions of the particular manufacturer. Instructions are often available on shingle bundle wrappers or can view on-line, by visiting the manufacturer’s website; prior to starting the work.
Typically the process begins by installing 1/3 of a full shingle at the rake edge /roof eaves junction. Immediately next to the first laid shingle, install a full shingle.
On the next course up; again staring at the rake edge, install a ½ cut shingle, and then a full shingle next to it. On the third course, apply a ¾ cut shingle, beginning again at the rake edge. Next, to it apply a full shingle. On the fourth course, apply a full shingle, starting at the rake edge.
The process can be repeated as one progresses courses up to the roof slope. Simultaneously, full shingles can be applied horizontally across the roof’s surface.
Following this described method prevents a condition referred to as “racking” of the shingles. Racking of the shingles involves installing each proceeding course of shingles with a six inch offset from the prior laid shingle. What can occur is that as building surfaces expand and contract; as a result of thermal movement between winter and summer temperature variations; the result can be shingle courses which are left with the appearance of joints spread open between shingles. The appearance of the mass of the roof can show as a “sawtooth” look up the roof slope, on a diagonal plane.
It is important to emphasize that one should follow the particular shingle manufacturer’s installation instructions. What one manufacturer may accept, may not be applicable to another manufacturer.
All manufacturers require that shingles are to be nailed using a minimum of five nails, which should be placed in strategic areas (usually referred to as the nailing zone or nailing strip) area of the shingles. On certain applications such as mansard walls, or pitches above 14/12; double nailing may be required by the manufacturer. This is often referred to as “storm nailing”. Such techniques are suggested for regions known for high winds like coastal areas, or where open fields may be a consideration.
Always apply the shingles so there is a minimum of 1-1/2” overhang at the roof eaves area and ½” at the rake edges.
When encountering various roof appliances such as plumber vents, heat pipes, skylights or chimneys; there are specific requirements in terms of techniques, and flashing components that must be used to insure a water-tight seal in these vulnerable areas. While it is difficult and time-consuming to describe each individual detail of the work involved; a do it yourself person can accomplish such details in two ways. Either hire a pro to complete such detail work, or view video tutorials on-line, and in conjunction with manufacturer supplied instructions.
Critical areas such as roof to wall junctions require metal flashings to be installed. Where a roof slope meets the side of a dormer, or a vertical wall, or a curb-mounted skylight; L-shaped pieces of metal called “step flashings” are inter-woven between each shingle course which in turn, but against the wall surface. A secondary metal flashing is installed over the exposed metal step flashing on the vertical wall, to seal to the wall. Such metal is referred to as “counter-flashing”.
Where shingles slopes adjoin a horizontal wall surface, “wall flashing” is installed. This metal detail essentially has a bent profile which extends up the wall surface and slopes onto the roof over the shingles. Both wall and counter flashings are typically caulked at the top leading edge.
Chimneys and curb -mounted skylights require step flashings to be installed along their sides, and then cloaked in counter-flashings. Back pans and front pans are installed at the front and back of these items respectively. All of the metal components are lock –seamed at the corners to adjoin each metal component to the others. Back pans shed water at the rear of the appliance, and front pans shed water over the shingle surface at the front of the appliance. On roofs having a pitch of 8/12 or greater, often a metal “saddle” detail is configured behind a chimney for the purpose of shedding water.
Where skylights are concerned, it is often suggested to replace older units when replacing a shingle roof. Perimeter frame to glass junctions can fail due to movement, age, and weathering. One should inspect for signs of moisture between the glass or acrylic lenses.
8) Ventilation is the key to making roofing shingles last.
It is additionally a requirement of all shingle manufacturers for the validation of their warranties. A balanced ventilation system for a shingle roof installation requires 50% intake of air at the roof eaves areas, and 50% exhaust venting of hot, moist attic air, at the top of the roof. Calculations for the number of vents required in soffit areas and roof attics can be determined by checking with manufacturers such as AIRVENT™, whom publish information and guides on the subject.
In general, terms, using the correct type of vent for the type of attic is very important. Cathedral or vaulted ceilings, or homes that have interrupted attic designs, should utilize ridge venting at the peak of the roof.
Conventional open designed attics can utilize individual static or “turtle” type vents. Such vents have specific capacities for exhausting heat from the attic space; calculated in cubic feet per minute (CFM ratings).
The under-hangs of roofs known as “soffits”, should have individual or continuous vent panels. Such venting can be achieved by installing aluminum soffit cladding with perforations.
Many of today’s modern homes are built with or retrofitted with increased levels of insulation. High-efficiency doors, windows, and furnaces have contributed to making homes more thermally efficient, but tighter and more prone to issues of ice damming, and condensation, if ventilation is not properly accounted for in the building envelope.
Where roof shingles are concerned, excess heat builds up in attics can result in superheating of the materials. In winter months, condensation can result leading to deck rot over time.
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9) A good quality shingle roof
It is a key component to protecting what most people would consider their single biggest investment; their home. So whether a person decides to install their own roof shingles, or to enlist the services of a professional roofing contractor; it is important to do research and understand what is involved to perform the job right.